@Article{MedeirosTayTakBatGob:2003:PrDiWi,
               author = "Medeiros, Amauri Fragoso de and Taylor, Michael J. and Takahashi, 
                         Hisao and Batista, Paulo Prado and Gobbi, Delano",
          affiliation = "{Universidade Federal Campina Grande (UFCG)} and {Utah State 
                         University} and {Instituto Nacional de Pesquisas Espaciais (INPE)} 
                         and {Instituto Nacional de Pesquisas Espaciais (INPE)} and 
                         {Instituto Nacional de Pesquisas Espaciais (INPE)}",
                title = "An investigation of gravity wave activity in the low-latitude 
                         upper mesosphere: Propagation direction and wind filtering",
              journal = "Journal of Geophysical Research",
                 year = "2003",
               volume = "108",
               number = "D14",
                pages = "4411 (8pp.)",
                month = "July",
             keywords = "airglow, winds, gravity waves, wind filtering, imager, nightglow 
                         emissions, critical level, shear flow, airglow, atmosphere, 
                         spectra, middle.",
             abstract = "An all-sky charge-coupled device imager capable of measuring wave 
                         structure in the OH, O-2, and O I (557.7 nm) airglow emissions was 
                         operated at Cachoeira Paulista, Brazil (23degreesS, 45degreesW), 
                         for 2 years in collaboration with Utah State University, Logan. 
                         The dominant quasi-monochromatic gravity wave components 
                         investigated over a similar to1 year period (September 1998 to 
                         October 1999) have been extracted, and their seasonal variations 
                         have been measured. A total of 283 wave events were measured, 
                         exhibiting horizontal wavelengths from 5 to 60 km, observed 
                         periods from 5 to 35 min, and horizontal phase speeds of up to 
                         similar to80 m s(-1). The large-scale {"}band'' wave patterns 
                         (horizontal wavelength between 10 and 60 km) exhibited a clear 
                         seasonal dependence on the horizontal propagation direction, 
                         propagating toward the southeast during the summer months and 
                         toward the northwest during the winter. The direction of 
                         propagation was observed to change abruptly around the equinox 
                         period in mid March and at the end of September. Using a numerical 
                         simulation of gravity wave propagation in a seasonally variable 
                         climatological wind field, we have determined that the observed 
                         anisotropy in the wave propagation directions can be attributed to 
                         a strong filtering of the waves in the middle atmosphere by 
                         stratospheric winds.",
           copyholder = "SID/SCD",
                  doi = "10.1029/2002JD002593",
                  url = "http://dx.doi.org/10.1029/2002JD002593",
                 issn = "0148-0227 and 2156-2202",
             language = "en",
           targetfile = "jgrd9984.pdf",
        urlaccessdate = "28 abr. 2024"
}